My Blood Sugar Level was 45, another low?

Ive been trying to monitor my BG levels more lately as I have been feeling really sick for months with severe kidney pain-every day. The kidney pain is non-stop throbbing regardless of what I eat or drink. I drink water all the time as to help my body stay healthy but it does not help. I get times through the day when I reach a real low and feel like Im going to faint and I see spots and squiggles. I fasted last night from 9pm-6am and tested and I was at like 78. I tested earlier when I started having an "episode" and my sugar level was 45. I had two small cookies because it was unbearable and I didn't want to p out at work. Now Im dizzy for the rest of the day with a severe headache. This is a daily occurrence. Sometimes I reach the brink of fainting. Should I just go to the ER and get checked out and checked in or should I wait to schedule an appointment. My sugar as of 6pm was 107 after eating. Its now 7pm and I feel horrible again. Please advise, thanks in advance.